Field of Invention
The present invention relates to a fan device.
Description of Related Art
A conventional fan device used in a laptop computer includes a housing and blades. The blades are disposed in the housing. When a motor drives the blades, heat can be dissipated from the interior of the laptop computer.
The size of the fan device is limited by the inner space of the laptop computer, so that the thickness of the housing is usually thin and influences the anti-pressure strength of the housing. For example, the housing includes a cover and a base. When the cover is pressed by an external force, the cover with insufficient strength can be interfered with the blades. In order to solve the interference between the cover and the blades, the manufactures of the fan device often adopt the following methods:
First of all, the thickness of the cover is increased. However, increasing the thickness of the cover increases the volume of the fan device, and thus the fan device cannot be installed in a limited space if required. Again, the thickness of the cover can be increased by decreasing the height of the blades. In this method, although the volume of the fan device is the same, the blowing rate (working area) of the fan device is reduced.
Secondly, an additional concave-convex structure is disposed on the cover. When the concave-convex structure is disposed on the cover, the concave-convex structure increases the air resistance of the fan device and decreases the blowing rate of the fan device, and thus the heat dissipation rate of the fan device is reduced.
Furthermore, a support pillar is disposed between the cover and the base. The support pillar between the cover and the base is formed on a metal base by plastic injection molding. The support pillar has a certain volume, and the airflow is likely to be blocked by the support pillar, thus decreasing the blowing rate of the fan device. As a result, the heat dissipation efficiency of the fan device is reduced.